Cab and Body Maintenance Instructions (Cont)
This task covers:
b. Follow-on Maintenance
MOS 63S, Heavy wheel vehicle mechanic
TM or Para
TM 9-2320-279-10 Shut off engine.
16-49.4. RELIEF VALVE PRESSURE ADJUSTMENT (M978) (MODEL C).
Special Environmental Conditions
General Safety Instructions
No smoking, flame, sparks, and hot
or glowing objects within 50 ft (15 m)
Never adjust relief valve so that
personnel must stand on strongback (5)
to operate latch (1). If there is any
residual pressure in tank when relief
valve is open, personnel may lose their
balance and fall. Failure to comply
may result in injury or death to
Failure to relieve tank pressure may
result in sudden, unexpected loss of
pressure. Failure to comply may result
in injury or death to personnel.
Relieve vapor pressure or vacuum from cargo tank.
Open latch (1) to remove plastic plug (2).
Place wrench over nut (3) and insert hex key into stem (4).
Hold hex key stationary and turn wrench counterclockwise two full turns to loosen nut (3).
Pressure may now be adjusted by rotating stem (4) with hex key.